Most helicopters have a single, main rotor but these helicopters also require a separate rotor to overcome torque generated by the main rotor. The single, main rotor blades are generally oriented to rotate in a horizontal plane and the separate rotor blades, often positioned in the tail of the craft, are generally oriented to rotate in a vertical plane.
The single main rotor of a helicopter, as the engine rotates it, creates a counter-torque. The torque causes the body of the helicopter to turn or rotate in the opposite direction that the rotor rotates. The tail rotor, provided with variable pitched blades, through its rotation, either pushes or pulls against the tail to counter the torque imparted by the main rotor to the body of the helicopter.
If the tail rotor fails in flight, engine torque can no longer be countered by the tail rotor, and uncontrolled spinning of the aircraft, driven by the torque generated by the main rotor rotation, is a common result. The pilot has to identify and diagnose the type of tail rotor failure and react accordingly with the correct control strategy within a few seconds to prevent the helicopter from reaching an uncontrollable flight state. There is a need for a device that can automatically provide sufficient torque counter-action upon the loss or failure of a tail rotor to increase the amount of time a pilot has to react to the tail rotor failure thereby increasing the pilot's chances of ultimately safely landing the helicopter. There is also need for a device that can provide sufficient torque counter-action upon the loss or failure of a tail rotor to provide enough directional stability at normal cruising speeds so that a pilot can continue on course or maintain altitude until a suitable landing area is reached.